Only one eye drop ingredient is FDA-approved to grow eyelashes: bimatoprost, sold under the brand name Latisse. It requires a prescription, comes as a 0.03% solution, and is applied along the upper lash line once daily. Several glaucoma eye drops contain similar ingredients that also cause lash growth as a side effect, which is actually how Latisse was discovered in the first place.
How Bimatoprost Grows Lashes
Your eyelashes cycle through three phases: growing, resting, and shedding. At any given time, only some of your lash follicles are actively growing. Bimatoprost works by increasing the percentage of follicles in the active growth phase at once, and it keeps them there longer than they’d normally stay. The result is lashes that are longer, thicker, and darker because more of them are growing simultaneously and each individual lash has more time to lengthen before it enters its resting phase.
Latisse vs. Glaucoma Eye Drops
Bimatoprost was originally developed to treat glaucoma under the brand name Lumigan. Doctors noticed their glaucoma patients were growing remarkably long, thick eyelashes as a side effect. That observation led to Latisse, which contains the same active ingredient at the same 0.03% concentration but is packaged with disposable applicators for the lash line rather than as traditional eye drops.
Other glaucoma drops in the same drug class, including latanoprost and travoprost, can also trigger lash growth. Some people use these off-label for cosmetic purposes, but none of them carry FDA approval for eyelash growth. Latisse remains the only FDA-approved product for that specific use, and it requires a prescription. It is not approved for anyone under 18.
What Results Look Like
Latisse is not instant. Most people start noticing changes after about 30 to 60 days of daily use. Lashes reach their maximum length, thickness, and darkness around the 16-week mark. That means you’re committing to roughly four months of nightly application before seeing the full effect.
The results are also not permanent. If you stop using Latisse, your lashes gradually return to their natural growth cycle. There’s no sharp “shedding event,” but over several weeks to months, the extra length and fullness fade as your lashes cycle back to their baseline. Many people switch to applying every other day or a few times per week once they’ve reached their desired results, which can help maintain the effect while using less product.
Side Effects Worth Knowing About
The most commonly discussed side effects are mild: redness, itching, or darkening of the skin along the lash line. These are usually manageable and often resolve if you’re careful about where the solution lands. But there’s a more significant concern that gets less attention.
Prostaglandin-based drops, including bimatoprost, latanoprost, and travoprost, can cause fat loss around the eye socket over time. This condition, called prostaglandin-associated periorbitopathy, makes the upper eyelid appear more hollow or sunken. In one study, deepening of the upper lid crease appeared in 80% of bimatoprost users who developed this condition, 45% of travoprost users, and about 16% of latanoprost users. The fat loss tends to be the earliest visible sign, and older patients are more susceptible.
For someone using Latisse on the lash line rather than putting drops directly into the eye for glaucoma, the exposure is lower, and the risk is reduced. But it’s not zero, especially with long-term use. Bimatoprost can also cause permanent darkening of the iris in people with lighter-colored eyes if it gets into the eye itself, which is why careful application matters.
Over-the-Counter Lash Serums
Walk through any beauty aisle and you’ll find dozens of lash serums claiming to boost growth. These fall into two broad categories: those that contain prostaglandin analogs (similar in structure to bimatoprost but marketed as cosmetics rather than drugs) and those that rely on peptides, biotin, or other non-prostaglandin ingredients.
The prostaglandin-based OTC serums can produce noticeable results, but they occupy a regulatory gray area. They’re formulated to be similar enough to work while staying technically different enough to avoid needing FDA approval as a drug. That means less oversight on safety and efficacy. A comprehensive review of eyelash serums published in 2024 found that while bimatoprost has strong evidence behind it, other prostaglandin ingredients show potential but lack the same depth of study. Non-prostaglandin ingredients like peptides had even less formal evidence supporting their use for lash growth.
If you’re considering an OTC serum, the presence of a prostaglandin-related ingredient (often listed as isopropyl cloprostenate or similar) is the feature most likely to produce visible growth. Peptide-based serums may help condition lashes and reduce breakage, but they work through a different, less proven mechanism than the prescription option.
Practical Tips for Application
Latisse is applied to the upper lash line only, not the lower lashes and not directly into the eye. You use the provided sterile applicator to draw a thin line along the base of the upper lashes, similar to applying liquid eyeliner. The solution migrates to the lower lashes on its own through normal blinking.
Applying more product doesn’t speed up results. One drop per applicator, one stroke per eye, once per night is the recommended routine. Remove contact lenses before application and wait at least 15 minutes before reinserting them. Blot any excess that runs beyond the lash line to minimize skin darkening and reduce the amount entering the eye.